This doesn’t follow the usual movie arc which might make it seem unfinished or self indulgent but I can’t seem to mind. I would watch another hour of this meandering investigation. On my first watch it felt like Fincher lacked a clear point of view but now it’s clear to me that the case is less important than Graysmith. When he descends into the basement he’s shocked by his own willingness to walk into a death trap. But he can’t help himself because he’s so deeply obsessed with Zodiac. This is Fincher’s gift: depicting obsession.